Micro-electro mechanical system (MEMS) is an integrated device which can obtain information; perform information processing; and execute operations. A MEMS sensor can detect various external information including pressure, position, velocity, acceleration, magnetic field, temperature or humidity, etc; and convert these external information into electrical signals. Thus, these external information can be processed by the MEMS. A pressure sensor is a type of device, which can convert pressure signals into electric signals; and a MEMS capacitive sensor is a typical type of pressure sensors.
FIG. 1 illustrates an existing MEMS capacitive pressure sensor. As shown in FIG. 1, the MEMS capacitive pressure sensor includes a substrate 100. The substrate 100 may include a semiconductor substrate (not shown), a plurality of semiconductor devices (not shown), such as CMOS devices, etc., on the semiconductor substrate, electrical interconnection structures electrically connecting the semiconductor devices, and a dielectric layer isolating the semiconductor devices and the interconnection structures. The MEMS capacitive pressure sensor also includes a first electrode layer 101 on the substrate 100. The first electrode layer 101 is electrically connected with the semiconductor devices in the substrate 100 through the electrical interconnection structures. Further, the MEMS capacitive pressure sensor includes a second electrode layer 102 on the substrate 100; and a chamber 103 is formed between the first electrode layer 101 and the second electrode layer 102. The chamber 103 electrically isolates the first electrode layer 101 and the second electrode layer 102. Further, the MEMS capacitive pressure sensor also includes a dielectric layer 104 on a surface of the second electrode layer 103 and a surface of the substrate 100. A portion of the second electrode layer 102 is exposed by the dielectric layer 104.
The first electrode layer 101, the second electrode layer 102 and the chamber 103 form a capacitive structure. When a pressure is applied on the second electrode layer 102, the second electrode layer 102 is deformed; and the distance between the first electrode layer 101 and the second electrode layer 102 changes. Thus, the capacitance of the capacitive structure changes. Because the pressure on the second electrode layer 102 is corresponding to the capacitance of the capacitive structure, the pressure on the second electrode layer 102 can be converted into an output signal of the capacitive structure.
However, the sensibility of the capacitive structure may have a certain limitation, and may be unable to match requirements of continuous technology developments. The disclosed device structures, methods and systems are directed to solve one or more problems set forth above and other problems.